Apparatus for controlling thermal growth in condensers

ABSTRACT

A condenser shell structure having a trough formed by an inner wall spaced from the outer shell structure and extending upwardly from the condenser support plane to a region adjacent the flange connection with the exhaust duct of a steam turbine operable at variable exhaust temperature. The trough is continuously provided with condensate from the condenser hot well at approximately saturation temperature, thereby to maintain the condenser shell temperature at saturation temperature for the exhaust steam pressure with attendant minimization of thermal growth of the condenser shell. The turbine may thus be supported by the condenser with minimal movement of the turbine that could otherwise cause misalignment of associated gearing and coupling members.

United States Patent 1191 Kasschau et a1.

1451 Apr. 23, 1974 APPARATUS FOR CONTROLLING THERMAL GROWTH INCONDENSERS [75] inventors: Kenneth Kasschau, Los Altos; John W. Ward,Sunnyvale, both of Calif.

[7 3] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: June 12,-1972 [21] Appl. No.: 261,895

[52] U.S.Cl.....i .L 60/692 51 Int. Cl. Folk 9/00 [58] Field of Search60/95 A [56] 7 References Cited 1 UNITED STATES PATENTS 1,781,10811/1930 Grace 60/95 A UX 1,793,641 2/1931 Schmidt .Q 60/95 A X FOREIGNPATENTS OR APPLICATIONS 280,920 12/1914 Germany 60/95 A 395,581 5/1924Germany- 1 60/95 A 549,433 4/1932 Germany ..1 60/95 A WATER OUT PrimaryExaminer-Edgar W. Geoghegan Assistant Examiner-H. Burks, Sr. Attorney,Agent, or FirmF. J. Baehr, Jr.

[57 ABSTRACT A condenser shell structure having a trough formed by aninner wall spaced from the outer shell structure and extendingupwardly'from the condenser support plane to a region adjacent theflange connection with the exhaust duct of a steam turbine operable atvariable exhaust temperature. The trough is continuously provided withcondensate from the condenser hot well at approximately saturationtemperature, thereby to maintain the condenser shell temperature atsaturation temperature for the exhaust steam pressure with attendantminimization of thermal growth of the condenser shell.

The turbine may thus be supported by the condenser with minimal movementof the turbine that could otherwise cause misalignment of associatedgearing and coupling members.

5 Claims, 5 Drawing Figures WATER l N TO STEAM GENERATOR FATENTEIWH /3mm 31805518 xHI -EI 1 Hi 3 WATER TO STEAM GENERATOR WAT E R OUT pmm nm23 mm A 34805 .51 8

sumaura T0 STEAM GENERATOR PIC-3.4

WATER OUT BACKGROUND OF THE INVENTION It has heretofore been the usualpractice by the assignee of this invention, in the marine turbine art,to support the steam turbine on a base or pedestal structure and hangthe steam condenser from the turbine. With this arrangement, temperatureexcursions of the condenser shell occasioned by the wide range ofturbine exhaust temperature attained during operation, with attendantthermal growth, could have little if any effect on the turbine mountingposition. Accordingly critical alignment of the turbine shaft with itsassociated gearing and coupling members could be maintained during suchwide range of temperature.

However, marine turbine horsepower ratings are constantly increasingwith attendant increase in size and weight of the turbine and thecondenser. Supporting the heavier condenser is becoming a significantproblem, particularly with respect to the interface connection betweenthe turbine and the condenser.

Accordingly, it is desirable to mount the turbine on the condenser.However, such an arrangementcreates a difficult problem with regard toalignment of the turbine and its driving connection with the reductiongearing, since thermal growth of the condenser shell will inherentlyshift the turbine out of its axially aligned position with respect tothe gearing and shaft coupling members.

SUMMARY OF THE INVENTION In accordance with the teachings of thisinvention, there is provided a marine turbine and condenser structure inwhich the turbine is mounted on the condenser shell and supportedthereby. The condenser shell structure has an internal trough formedadjacent the condenser support plate and extending upwardly to a regionadjacent its steam inlet flange, which inlet flange is connected to thesteam exhaust structure flange of the turbine.

The trough is continuously provided with water during operation, and ismaintained at'or near the saturation temperature for thesteam at theexhaust pressure. The shell of the condenser is thusheld at thetemperature of the water by direct contact therewith. Thus, even thoughthe turbine may be exhausting at a high temperature (as when driving inthe astem direction) but at low pressure (due tototal heat load andcondenser characteristics) the condenser shell temperature will bemaintained substantially at the saturated steam temperature for theprevailing condenser pressure and will not be strongly influenced by thehigh temperature of the exhausting steam.

The water for the trough is preferably condensate from the condenserhot-well which is maintained near the saturation temperature for theprevailing low condenser pressure. Excess condensate is continuouslydrawn off, preferably by overflow conduit means and returned to thehot-well of the condenser. Hence, the overflow is prevented from fallingonto the condenser tubes or being picked up by the high velocity of theincoming turbine exhaust steam.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an end view of a steam turbinesupported by a condenser having one embodiment of the inventionincorporated therein, with portions cut away to show internal structureof the condenser;

FIG. 2 is a longitudinal view of the steam turbine shown in FIG. 1 withthe condenser in cross-section;

FIG. 3 is an enlarged fragmentary view of the upper right-hand portionof the condenser, as viewed in FIG. 2,'to show details of the internaltrough structure; and

FIGS. 4 and 5 are views similar to FIGS. 1 and 2 but showing anotherembodiment of the invention.

DETAILED DESCRIPTION OF HE PREFERRED EMBODIMENT Referring to thedrawings in detail, FIGS. 1 and 2 show a first embodiment of theinvention in which a steam' turbine is provided with a steam condenser12 incorporating the invention. The turbine shown in the example is amarine propulsion turbine of the low pressure type, which, as well knownin the art, is supplied by motive steam afterparti'al expansion in ahigh pressure turbine (not shown). The turbine 10 has an output shaft14, which is drivingly connected to a ships propeller through reductiongearing by a suitable coupling (not shown). 1

The turbine 10 has a steam inlet 15 for driving the turbine shaft in theahead mode, i.e., in a direction to propel the ship forward, and analternately employed steam inlet 16 for driving the turbine shaft 14 inthe astern mode, i.e., in a direction to propel the ship rearward.

The turbine 10 is of the condensing type, i.e., after the energy of themotive steam is dissipated by the turbine, the spent steam is directedthrough an exhaust outlet 18 into the condenser 12.

The condenser 12 is of the tube-and-shell type and includes a condenserouter shell structure 20 having a bundle of heat-exchange tubes 21disposed therein and extending therethrough in a direction transverse tothe axis A of the turbine 10. The tubes are received at their oppositeends in suitable tube sheets 22 and 23 which together with suitablechannel heads 25 and 27 form respective inlet and outlet water chambers28 and 29 disposed in fluid communication with the tubes 21.

The channel head 25 is provided'with an inlet nozzle 30 and the channelhead 27 'is provided with an outlet nozzle 31. Coolant water, from anysuitable source (not shown) such as the sea is admitted to the inletnozzle 30, from whence it flows into the inlet chamber 28 and thencethrough the tubes 21 to the outlet chamber 29. During its flow throughthe tubes 21, the coolant water removes heat from the turbine exhauststeam thereby condensing it. The thus heated coolant water is thendirected from the outlet nozzle 31 back to the sea.

The condenser shell structure 20 is provided with a sump or hot-wellportion 33 at its bottom end to collect the condensate, and an outletconduit 34 is provided at the bottom of the hot-well 33 for removing thecondensate from the condenser. A pump 35 of any suitable type isinterposed in the outlet conduit 34 for pumping the condensate back to asuitable steam generator (not shown) for re.-vaporization.

As best shown in FIG. 2, the condenser 12 is disposed in an opening 36in a-ships structure 37 and suspended therein in a support plane P-Pextending through the upper portion of the outer shell 20 by a pair ofcondenser support structures 40. The condenser support structures 40 aredisposed externally of the outer shell walls 41 and 42 and each comprisea lower horizontal flange member 43, an upper horizontal flange member44 and a plurality of spaced reinforcing gussets 45. The lower flange 43bears on the upper surface of the ships structure 37 to support thecondenser thereon, while the upper flange 44 bears on the bottom of theturbine casing flange 40 to support the turbine thereon.

With the above arrangement, the entire weight of the turbine 10 issupported by the portion of the outer shell structure 20 of thecondenser lying between the lower flange 43 and the upper flange 44.Accordingly, the vertical position of the turbine shaft 14 is influencedconsiderably by the thermal expansion characteristics of the condenserouter shell structure during a heating period when the turbine 10 is inoperation, taking as a point of reference, the at rest period when theturbine is notin operation and the temperature of the outer shellstructure is at ambient temperature.

The critical portion of the outer shell structure 20 is that peripheralportion 47 lying between the upper and lower support flange members 44and 43, respectively.

In accordance with the invention, in order to minimize the thermalgrowth of the outer shell portion 47, an inner wall structure 50 isconnected to the outer wall member 42 by a bottom wall member 51,thereby providing an elongated open water passage or trough 52communicating with the interior 53 of the condenser.

As best shown in FIGS. 1 and 3, a distribution plate 55 is attached tothe outer wall 42 but is disposed in slightly spaced relation with theinner wall 50. If desired, the distribution plate 55 may be providedwith a plurality of spaced perforations 56. The distribution plate isdisposed in an intermediate position in the trough 52, and a flangedconnector 57 inserted in the outer condenser shell 20 provides an inlet58 for water into the trough 52 below the distribution plate 55, as willbe subsequently described.

Also, to prevent entrance of highvelocity steam into the trough 52, aninclined baffle plate 60 is attached to the outer wall 42 and disposedin a manner toextend across the inner wall member 50. In the exampleshown and described above, the outer shell wall 42 is a planar memberextending vertically. Hence, the inner wall'portion 50 is also planarand vertically disposed to impart a uniform cross-sectional shape to thetrough 52.

However, the outer shell wall 41 has an upper portion 61 (FIG. 2)inclined inwardly at an angle of about 45. Accordingly, in thisportion'an inner wall member 62 is provided with an inwardly inclinedupper portion 63 conforming to the outer wall portion 61, thereby toprovide an elongated trough 65 of uniform crosssectional shape in thisportion of the condenser. Here again, an inclined baffle plate 66(similar to baffle plate 60) is arranged to extend across the inner wallportion 63 to prevent admission of high velocity steam into the trough65.

A second flanged connector 57a inserted in the outer wall 41 may beprovided to admit water into the trough 65.

As best shown in FIG. 1, the opposite ends of the trough 52 areterminated and defined by a pair of transverse wall members 67 and 68connected at their bottom portion to the bottom plate 51 and at theirupper portion to the peripheral shell portion 47.

The trough 65 is terminated at its ends in a manner similar to thetrough 52 in a manner which is now clear and need not be shown.

The inlet connectors 57 and 57a are connected by parallel conduitsindicated by 70, 71 to the discharge end of the pump 35, so that inoperation a part of the condensate usually returned to the steamgenerator is supplied to the troughs 52 and 65.

In operation, as the vitiated steam from the turbine 10 is condensed inthe condenser 12, it drops to the hot-well 33 where it is withdrawnthrough the conduit 34 by the pump 35 for delivery to the steamgenerator (not shown) for re-evaporation and returned to the turbine 10as motive steam in a closed cycle, as well ment directly onto thesurface of the condenser tubes 21 one or more overflow pipes 73 may beattached to the inner wall 50. And in a similar manner, one or moreoverflow pipes 74 may be attached to the the inner wall 62. The pipes 73and 74 extend along the outer boundary: of the tube bundle B (FIG. 2)and downwardly therepast to direct such overflow directly to the hotwell33. 1

Since the condensate from the hot well is constantly provided to thetroughs 52 and 65, and since this condensate is approximately atsaturation temperature for the low pressure conditions in the condenser,the outer shell 20 of the condenser is maintained at the temperature ofthe condensate in the condenser regardless of the tem-perature of theexhaust steam before condensing. Thus, even when the turbine may beexhausting at a high tempera-ture (as when going astern) but at lowpressure (due to total heat load) the condenser outer shell will bemain-tained at the saturated steam temperature for the pressure.Accordingly thermally induced growth of the outer shell is minimized, atleast in the region between the mounting plane P-P' and the turbinemounting flange 44, thereby substantially eliminating any movement ofthe turbine 10 that could otherwise cause misalignment of the turbineshaft 14 and its associated gearing and coupling members.

In FIGS. 4 and 5 there is shown another embodi-ment of the invention.This embodiment is generally simi-lar to the first embodiment describedabove. However, in this embodiment the turbine 10 is mounted upon andsupport-ed by a condenser 75 which, in turn is mounted upon-andsupported at its bottom end by a foundation structure 77.

It will be noted that with this arrangement the entire outer shellstructure 78 of the condenser 76 is disposed between the condensermounting plane MP-MP' and the turbine exhaust flange 80. Accordingly theentire shell is susceptible to thermal growth, in operation, withattendant undesirable misaligning movement of the turbine.

In accordance with the invention, thermal growth of the outer shell 78is minimized by provision of a pair of vertically elongated troughstructures 80 and 81 that extend from the hot-well 83 upwardlysubstantially to the condenser mounting flange 84.

As in the first embodiment, the troughs 80 and 81 are disposed intransversely opposed relation (see FIG. 5) on opposite sides of the tubebundle 85 and defined by the outer side walls 86, 87 of the condensershell and inner spaced walls 88, 89, respectively.

Accordingly, in this embodiment, the troughs 80 and 81 hold a body ofhot-well condensate that extends for substantially the entire verticalextent of the condenser outer walls 86 and 87.

In all other respects, this embodiment may be similar to the firstembodiment and need not be further described.

It will now be seen that the invention provides an arrangement in-whichthe outer shell structure of a steam condenser is prevented fromoverheating in an unpredictable manner and in which the thermal growthis controlled in operation to a predictable minimum degree of expansion.

It will further be seen that with the above arrangement, the turbine maybe mounted upon the condenser and supported thereby, with full assurancethat deleterious movement of the turbine, during a wide range ofoperation, is minimized.

It must further be pointed out that in both embodiments the troughs orwater passages are on opposite sides of the tube bundle andsubstantially coextensive therewith. The end portions of the condenserouter shell structure do not necessarily require the trough treatmentfor two reasons, first, the coolant water in the channelheads and tubesprovide an optimum heat sink for the adjacent portions of the condensershell structure, and, second, the end portions of the shell are notnormally in line between the shell support 17 or 37 and turbine 10,sothat thermal growth would not influence the turbine location.

We claim:

1. In combination, a steam turbine, a condenser for condensing steamexhausted from said turbine, said condenser having a shell structure andan exhaust structure connecting said condenser shell structure to saidturbine, said turbine being adapted to exhaust steam to said condenserat varying temperatures, a condensate pump for removing condensate fromsaid condenser, an upwardly extending inner wall joined to one of saidstructures to jointly form therewith a water wall in fluid communicationwith the interior of the condenser and with said condensate pump, andoverflow means associated with said water wall, whereby condensate iscirculated in said water wall to maintain the temperature of said onestructure generally at a temperature equal to that of the condensateregardless of the temperature of the exhaust steam.

2. The combination recited in claim 1, wherein the condenser comprises aplurality of heat exchanger tubes for condensing the turbine exhauststeam, a hot well for collecting the condensate and means for directingcondensate from said overflow means to said hot well.

3. The combination recited in claim 1, wherein the one structure is theexhaust structure.

4. The combination recited in claim 1, wherein the one structure is thecondenser shell structure.

5. The combination recited in claim 1 and further comprising adistribution plate disposed in said water wall to distribute thecondensate over the entire water wall.

1. In combination, a steam turbine, a condenser for condensing steamexhausted from said turbine, said condenser having a shell structure andan exhaust structure connecting said condenser shell structure to saidturbine, said turbine being adapted to exhaust steam to said condenserat varying temperatures, a condensate pump for removing condensate fromsaid condenser, an upwardly extending inner wall joined to one of saidstructures to jointly form therewith a water wall in fluid communicationwith the interior of the condenser and with said condensate pump, andoverflow means associated with said water wall, whereby condensate iscirculated in said water wall to maintain the temperature of said onestructure generally at a temperature equal to that of the condensateregardless of the temperature of the exhaust steam.
 2. The combinationrecited in claim 1, wherein the condenser comprises a plurality of heatexchanger tubes for condensing the turbine exhaust steam, a hot well forcollecting the condensate and means for directing condensate from saidoverflow means to said hot well.
 3. The combination recited in claim 1,wherein the one structure is the exhaust structure.
 4. The combinationrecited in claim 1, wherein the one structure is the condenser shellstructure.
 5. The combination recited in claim 1 and further comprisinga distribution plate disposed in said water wall to distribute thecondensate over the entire water wall.